Spark plug



May 19, 1925.

y F. F. GEBHARDT SPARK PLUG Filed Aug.r 2. 1922 fov . ralit Patented May 19, 1925.

UNITED STATES FRED F. GEBHARDT, 0F PITTSBURGH, PENNSYLVANIA.

SPARK PLUG'.

Be it known that I, FRED F. GEBHARDT, a citizen of the United States, residing at Pittsburgh, in the county of Alleghen and State of Pennsylvania, have inventer certain new and useful Improvements in Spark Plugs, of which the following is a specilication.

This invention relates to an improved s ark plug and seeks, as one of its principal oldjects, to provide a plug embodying a pluof spark gaps for insuring the depen able functioning of the plug.

The invention has as a further object to provide a plug which, in embodying aV lu rality of spark gaps will not only ten to insure positive ignition but will also tend to bring about more complete combustion than is the case with an ordinary plug so that fouling Will be correspondingly reduced while anengine may be efficiently operated with a leaner fuel mixture than would otherwise be the case. y

And the invention has as a still further object to provide a plug which will be sturdy in its construction and will accordingly be capable of resisting failure and wherein-the plug will be adapted for general use in connection with internal combustion engines.

Other and incidental objects will appear hereinafter.

In the drawings:

Figure l1 is a vertical sectional view through my improved spark plugy Figure 2 'is a bottom plan view of the device, and

Figure 3 is a detail perspective view showing one of the sparking terminals of the main electrode of the device.

ploy a shell 10 threaded at its lower end for engagement in the usual-spark plug opening of an engine cylinder and provided at its upper end with fiat faces to accommodate a wrench so that the plug may be readily applied or removed. Removab-ly fitting in the shell is an insulator 11 terminating near the lower end of the shell and providedwith a flat lower end face. This insulator is formed near its lower end with a shoulder 12 and interposed beneath said sh'oulder is an appropriate gasket 13, the shell being formed with an internal annular shoulder seating said gasket. Overlying the shoulder 12 is a similar gasket 14 and threaded into the Application led August 2, 1922. Serial No. 579,160.

upper Vend of the shell is a nut 15 surround- 'ing the insulator and bearing against said gasket for clamping the insulator in position. At its upper end the nut is provided with a flange 16 overhanging the shell and interposed between said ange and the shell is an appropriate gasket 17, the flange being preferably provided withflat facesse that a wrench may be applied thereto for removing the nut. Embedded in the insulator is a main electrode 18 extending axially of said* insulator and provided at its lower end with an annular head 19 disposed medially f of the shoulder 12. At its upper end, said electrode projects above the insulatorand surrounding said electrode is a washer 2() cemented to :the upper end face of the insulator. Threaded upon the electrode is a vbinding nut 21 for connecting a circuit wire with the electrode, the nut being adjustable for clamping said wire between the nut and the washer 20. Depending from the head 19 of the electrode through the lower end portion of the insulator is a plurality of sparking terminals 22. At their upper ends these terminals are provided with reduced studs 23 threaded into said head while atthe .lower end face of the insulator said terminals are likewise reduced to provide sparking points 24 extending below the lower end of the shell 10. As will be observed, four of the terminals 22 are preferably employed, said terminals extending in parallel relation to each other and, in the manufacture of the plug, the insulator 1]. will be preferably formed about the electrode 18 and said terminals so that `the material of the insulator will grip the terminals for securing said terj minals against counter-rotation to become In carrying the invention into effect, I emaccidentally detached from the electrode. Sunk into the lower end edge of the shell 10 to cooperate with the sparking Apoints 24* of the terminals 22 is a plurality of ground electrodes 25', one of said electrodes beingv provided in connection with .each of said terminals. A plurality of spark gaps are thus provided between said terminals and theground electrodes so that when a circuit is'closed through the plug, a spark will ocr cur at each of said gaps. The dependable operation of the plug will thus be enhanced and in producing a number of sparks, the `plug will tend to bring about more cour plete ignition of fuel gases. Fouling will thus be proportionately reduced while an at annular head -embedded in the insulator medially of said-shoulder, and a plurality of sparkin terminals provided at their upper ends wit reduced studs screwed into engagement with said head supporting the terminals to extend downwardly through the lower` end portion of the insulator embedded thereby to be held against accidental release by the insulator, said terminals being reduced at the lower end face of the insulator 20 to form sparking points.

.In testimony'whereof I affix my signature.

FRED F. GEBHARDT. [L s.] 

